Conservation of Western Monarchs

The monarch butterfly (Danaus plexippus plexippus) has experienced dramatic declines across North America. In response to a petition to list monarchs under the Endangered Species Act (ESA), USFWS established that a full review to consider monarch protection is warranted. To date, the eastern population of monarchs, which overwinters in Mexico, has been the main focus of research and conservation efforts. However, monarchs west of the Rocky Mountains are also in sharp decline (Pelton et al. 2016). Systematic citizen science monitoring, the Western Monarch Thanksgiving Count, started in 1997 with efforts by the Xerces Society and Mia Monroe. With Elizabeth Crone, Leone Brown, and colleagues at the Xerces Society for Invertebrate Conservation, we are finding that monarchs in the west have declined far more than previously thought (Schultz et al, in press). Our analyses suggest that historic populations of overwintering monarchs were around 10 million butterflies in the 1980s, and that fewer than 300,000 butterflies overwinter in these coastal California groves today.

Part of the challenge for conservation of this iconic species in the West is limited knowledge about their basic biology. Together with Xerces Society, Tufts University and collaborators at WSU Prosser, we have just embarked on a new project working with Department of Defense installations to gain a better understanding of where and when monarch butterflies breed across the west. We are working at sites in California, Oregon, Nevada, Idaho and Washington. The Department of Defense, as a public agency responsible for management of public lands, is extremely interested in efficient and effective conservation strategies which balance training needs with natural resource management. Gaining a greater understanding of monarch biology will help us focus resources and effort in places and times which are most likely to make important contributions to the monarch population. We are currently in the field with this project in 2017 and look forward to gaining a greater understanding on monarch biology as part of this work.